Selected Technique:
Dynamic Compaction
Treatment Area:
1,866 m²
Groupe Evex approached Menard Canada to improve the soil of the foundations and the slab under the multi-unit building at 678 rue de la Visitation in Saint-Charles-Borromée, Quebec. The area of the land to be improved was 1,866m2, including an overflow of 3m.
Ground Conditions
The geotechnical data extracted from the drilling reports indicated that the following soil profile was throughout the site.
- Asphalt and granular fill, with a thickness of approximately 0.12 m
- Backfill with sand and some silt with a thickness of approximately 1.2 m
- Sand deposit of fine to medium sand with traces of silt; Loose to medium compactness with an “N” index between 3 and 17
- Clay deposit: Silty clay with traces of a bit of sand
The water table was intercepted between 3.5 m and 4 m below surface level. The level of the water table can often fluctuate depending on the season.
Menard Canada Solution
Menard Canada carried out Dynamic Compaction using a conventional crane to densify the granular soils to a thickness of 6 to 7 meters. The treated soils had to meet a bearing capacity of 200 kPa at SLS for the isolated footings and for the strip footings. In addition, the total and differential settlements should not exceed 25mm and 19mm, respectively. The two boreholes with Piezocone Tests and the associated calculations showed that the criteria were effectively met.